Response:
Thorough analysis:
I believe that option 4 is the right choice
There are 28 combinations.
Step-by-step explanation: Initially, each of the seven bins holds one ball, leaving two remaining. If both are placed in the same bin, that offers 7 options. Conversely, if each remaining ball is positioned in different bins, the combination comes down to: 21 + 7 = 28 ways.